Beginners Guides:
Weather Balloons

by Neil Nelson

Weather balloons are used in the measurement and evaluation of the upper atmosphere. Information may be gathered during the ascent of the balloon through the atmosphere or during its or its motions once it has reached a predetermined altitude. However, the era of weather ballooning seem ending as other techniques such as radar, Geostationary satellites and aircraft. The use of balloons however, still remains widespread.

The balloons are normally filled with helium because of its very low density and because it is so unreactive.

There are different types of weather balloons -

1. Pilot balloons are small fairly small and are used to work out wind speeds at various altitudes.
2. Another small balloon is a ceiling balloon used to determine the altitude of clouds.
3. Much larger are Tear Drop balloons. They often carry a "Radiosonde" which are radio-transmitting instruments. "Radiosondes" are a major source of weather information. They typically carry aloft a compact combination of temperature, pressure, and humidity sensors. The tear drop balloon expands as it rises as the atmospheric pressure drops. They typically rise to 90000 feet (28000m) before it bursts. A cute parachute lowers the instruments to the ground. Such balloons are also used for horizontal sounding of the atmosphere.

Nowadays, many balloons are monitored from space by satellites.

4. Tetroons are tetrahedral balloons used for horizontal sounding and are designed to withstand extremely low pressures (without bursting like Tear Drops). They are used extensively in tracing low-level atmospheric currents by following their movements using radar; they are therefore increased the meteorologists understanding of turbulence, low level vertical motions and air pollution.



. 1999-2003 Justin Taylor / John Dray

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